A flash device and camera have at their coupling portions electrical terminals through which they are electrically connected to each other. Different signals are transmitted from the flash device to the camera and vice versa through the terminals. For example, a charging completion signal indicative of the completion of charging the flash condenser for energizing the flash tube is transmitted from the flash device to the camera and activates an indicator provided e.g. in the viewfinder of the camera. On the other hand, a synchronizing signal is sent from the camera to the flash device, which signal causes the flash device to flash.
It is desirable that all the pieces of information on the operation of the flash device should be indicated at a particular portion of the camera, e.g. the viewfinder. Recently developed complicated flash devices have more pieces of such information to be indicated, and so the number of the signals carrying the information is larger than before. A larger number of terminals on the coupling portions may permit a larger number of such signals to be transmitted, but it is undesirable to increase the number of the terminals. That is, in the case of a "grip" type flash device which is electrically connected to a camera by means of a multiple-conductor cable, an increase in number of the terminals leads to a corresponding increase in the number of component conductors between the flash device and camera. In the case of a "clip-on" type flash device which has a "foot" portion to be engaged with a corresponding "hot shoe" of a camera, it is difficult to provide many terminals insulated from each other in the tiny hot shoe.
It is thus an object of the present invention to provide a flash device in which the above-mentioned disadvantages are not encountered.